Power generation systems often include a power converter that is configured to convert an input power into a suitable power for application to a load, such as a generator, motor, electrical grid, or other suitable load. For instance, a power generation system, such as a wind turbine system, may include a power converter for converting variable frequency alternating current power generated at the generator into alternating current power at a grid frequency (e.g. 50Hz or 60 Hz) for application to a utility grid. An exemplary power generation system may generate AC power using a wind-driven doubly fed induction generator (DFIG). A power converter can regulate the flow of electrical power between the DFIG and the grid.
In many instances, power generation systems may be located in remote areas far from the loads they serve. This is particularly true for renewable energy sources, such as wind turbine systems, solar/photovoltaic systems, hydroelectric systems and/or the like. Typically, such power generation systems are connected to the electrical grid through an electrical system including long transmission lines connected to the grid using one or more breakers. Often such transmission lines include one or more series compensation elements (e.g., one or more capacitors) to facilitate reducing reactive power losses within the transmission lines, thereby increasing the power transfer capacity of the lines.
Unfortunately, when a power generation system is coupled to a series compensated transmission line, the system may experience sub-synchronous instability and may often trip unintentionally. This is a particularly true for wind-driven DFIG systems due to the DFIG exhibiting negative equivalent resistance in the frequency range below its nominal frequency. In such instance, the electrical system control components typically do not provide sufficient damping at such low frequency ranges, thereby resulting in system instability.
Accordingly, a system and method for controlling aspects of the operation of a power generation system that allow for enhanced system stability would be welcomed in the technology. In particular, a system and method for controlling aspects of the operation of a power generation system that allow for enhanced sub-synchronous stability when the system is connected to a series compensated transmission line would be welcomed in the technology.